Smoke rises over Gaza City after an Israeli strike on Friday, as Israel and Gaza militants resumed cross-border attacks on Friday after a three-day truce expired and Egyptian-brokered talks on a new border deal for blockaded Gaza hit a deadlock.

JERUSALEM — A three-day-old truce collapsed Friday in a new round of violence after Gaza militants resumed rocket attacks on Israel, drawing a wave of retaliatory airstrikes that killed at least five Palestinians, including three children.

The eruption of fighting shattered a brief calm in the monthlong war and dealt a blow to Egyptian-led efforts to secure a long-term cease-fire between the bitter enemies.

A delegation of Palestinian negotiators remained in Cairo in hopes of salvaging the talks. But participants said the negotiations were not going well, and Israel said it would not negotiate under fire. The Palestinian delegation met again late Friday with Egyptian mediators.

Azzam al-Ahmad, head of the Palestinian delegation, said the delegation would stay in Egypt until it reaches an agreement that “ensures” the rights of the Palestinian people. “We told Egyptians we are staying,” he told reporters.

The indirect talks are meant to bring an end to the deadliest round of fighting between Israel and Hamas since the Islamic militant group seized control of Gaza in 2007. In four weeks of violence, more than 1,900 Gazans have been killed, roughly three-quarters of them civilians, according to Palestinian and U.N. officials. Sixty-seven people were killed on the Israeli side, including three civilians.

The Palestinians are seeking an end to an Israel-Egyptian blockade imposed on Gaza after the Hamas takeover.

The blockade, which Israel says is needed to prevent arms smuggling, has restricted movement in and out of the territory of 1.8 million people and brought Gaza’s economy to a standstill. Israel says any long-term agreement must include guarantees that Hamas, an armed group sworn to Israel’s destruction, will give up its weapons.

In Cairo, Palestinian participants in the talks were pessimistic about the chances of a deal. They said Israel was opposing every Palestinian proposal for lifting the blockade.

For instance, the Palestinians are seeking greater movement of goods through Israeli-controlled cargo crossings, while Israel wants restrictions on “dual-use” items that could potentially be used for military purposes, they said.

Israel also was resisting demands to allow movement between Gaza and the West Bank — Palestinian territories that are located on opposite sides of Israel, they said.

“Israel in these talks wants to repackage the same old blockade. Our demands are ending the blockade and having free access for people and goods. This is what ending the blockade means. But Israel is not accepting that,” said Bassam Salhi, a Palestinian negotiator.

Negotiators said they expected to remain in Cairo for several days. But with violence resuming, it was unclear how much progress could be made.

The Israeli delegation to the Cairo talks left Egypt on Friday morning, and it was not clear if it would return. “There will not be negotiations under fire,” Israeli government spokesman Mark Regev said.

In Cairo, Khaled al-Batch, a leader of Islamic Jihad, a smaller militant group in Gaza, said that without a deal on easing the blockade, an informal truce might be the best that could be achieved.